Therapeutic instrumentation electrode

ABSTRACT

A medical electrode for applying electrical energy to or across the body of a patient which includes a paddle having a flat disclike contact plate electrode for intimate contact with the skin. Electrical energy is supplied to the plate along a ring disposed centrally thereof through a hollow right cone at whose apex the energy is applied. The paddle also includes an upper dielectric horizontal handle having a control switch through which a supply wire passes to and through a vertical dielectric rod to the cone apex. Disposed above the plate is a dielectric shield protector which is integral with the rod and extends outwardly past the plate.

United States Patent [4 June 20, 1972 Panico [54] THERAPEUTICINSTRUMENTATION ELECTRODE [72] Inventor: Joseph Panico, Arlington, Mass.

[73] Assignee: Health Systems, Inc., Woburn, Mass.

[22] Filed: July 17, 1970 [21] Appl. No.: 55,851

[52] U.S. Cl. ..128/404, 128/419 D [51] Int. Cl. ..A61'n H04 [58] FieldofSearch ..l28/404--418,4l9 D, 128/1721, DIG. 4

[56] References Cited UNITED STATES PATENTS 3,025,858 3/1962 Browner..128/418 1,363,807 12/1920 Murphy... ..128/417 3,196,877 7/1965Corbin..... ...128/419 D 3,258,013 6/1966 Druz ..L ..128/419 D we 7:4qr:

sou/7c:

Primary Examiner-William E. Kamm Att0rneyEdward F. Costigan [57]ABSTRACT A medical electrode for applying electrical energy to or acrossthe body of a patient which includes a paddle having a flat disc-likecontact plate electrode for intimate contact with the skin. Electricalenergy is supplied to the plate along a ring disposed centrally thereofthrough a hollow right cone at whose apex the energy is applied. Thepaddle also includes an upper dielectric horizontal handle having acontrol switch throughwhich a supply wire passes to and through avertical dielectric rod to the cone apex. Disposed above the plate is adielectric shield protector which is integral with the rod and extendsoutwardly past the plate.

7 Claims, 7 Drawing Figures m l/fI/Z P'A'TENTEDwnzo m2 3. 670. 736

saw 10F 2 INVENTOR. JOSEPH r1 PAN/c0 H/s HTTO/P/VE) THERAPEUTICINSTRUMENTATION ELECTRODE BACKGROUND OF THE INVENTION 1. Field of theInvention I The present invention relates to therapeutic medical devicesand more particularly pertains to body contact electrodes forelectro-therapeutic treatment wherein the electrical energy is appliedthrough the body in a unifonn current distribution between the surfacesof electrodes. It further pertains to a unique paddle structure for easeof operation and handling while protecting the operator.

2. Description of the Prior Art In the field of electro-therapeutic andcardiac medicine, it has been the general practice to apply electricalenergy to the body by means of a disc-like electrode which is suppliedby a central wire or cable from a suitable source. The entire electricalstructure is surrounded or encased in a dielectric jacket to form anupstanding handle with only the lower electrode surface exposed. Suchmedical devices have proved to be unsatisfactory in that they aredifficult to manipulate and handle and, more basically, when employed incardiac defibrillation, the current distribution through the body isconcentrated in a narrow channel between the centers of the paddleelectrodes thereby not encompassing the entire heart muscle.

SUMMARY OF THE INVENTION The general purpose of this invention is toprovide an electro-therapeutic medical paddle that has all theadvantages of similarly employed prior art devices and has none of theabove described disadvantages. To attain this, the present inventionprovides a unique electrode structure wherein the electric currentenergy is applied to the contact plate along a surface contact loopwhich is central thereof. Specifically, for a circular disc plate, thecurrent is applied along a ring which is equidistant from the center andthe outer edge thereof. One suitable structure therefore is a rightcircular hollow cone having its base central of the plate and thecurrent input at its apex whereby a uniform and stable currentdistribution is provided over the entire plate surface and through thebody.

An object of the present invention is to provide a reliable, simple,inexpensive, easily manipulated electro-therapeutic contact electrode.

Another object is to provide a contact electrode for use in cardiacdefibrillation which electrode, will develop a uniform currentdistribution over the entire electrode face and through the body.

Still another object is to provide a defibrillator paddle which willsupply a broad uniform current distribution sufficient to encompass theentire cardiac muscle.

A still further object is to provide a defibrillator paddle which may bereadily and easily handled by the operator with a positive controlswitch and a high voltage protector.

Other objects and many of the attendant advantages of the presentinvention will be readily appreciated as the same become betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I illustrates the current patternor distribution through a human body for conventional defibrillatorpaddle electrodes;

FIG. 2 illustrates the current distribution between defibrillatorpaddles made in accordance with the principle of this invention;

FIG. 3 is a cross-sectional view taken approximately along 33 of FIG. 4of a defibrillator paddle made in accordance with the principle of thepresent invention;

FIG. 4 is top elevation of the embodiment of the invention of FIG. 3;

FIG. 5 is a front elevation of the embodiment of FIG. 3;

FIG. 6 is another embodiment of the invention showing the basicstructure; and,

FIG. 7 is a bottom elevation of the embodiment for FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the illustration of FIG. 1,a pair of conventional defibrillator electrodes 10 and 11 are disposedon opposite sides of the patients chest directly across or in line withthe heart. The electrodes are connected to a source 112 of propervoltage and current is passed through the heart. The electrodes 10 and11 are connected to the source by wires 13 and 14 which are affixed tothe center of the disc electrodes. Thus, the current enters theelectrode at the center point 15 of one electrode and is expected todistribute equally throughout the lower surface 16 which is in contactwith the skin of the patient through some conductive paste or salinesolution (not shown). Two factors enter the present consideration,namely, the fact that initially the current enters at a specific pointand, that living tissue in response to current passing therethrough,offers a lower resistance or lowers its resistance along the currentpath in accordance with the current density. This resistance at peakenergy varies between 50 and 100 ohms between paddles and it is clearthat as current initially flows from the center, the re sistance betweenthe centers of the paddles will decrease and therefore increase thecurrent therealong. This effectively restricts the major portion of thecurrent into a narrow tubular region between electrode centers. Thecurrent distribution is illustrated by the field lines 17 which are mostdense at the center. It is well known that for the current to effectdefibrillation it must pass through or encompass all parts of the heartmuscle. The conventional defibrillator paddle with its restrictedcurrent distribution does not facilitate encompassing the entire cardiacmuscle and in order to overcome this inherent limitation and deficiencyin providing effective and efficient defibrillation, the overalldimensions of the pad dle electrode have been enlarged. This does noteffectively solve the problem since other drawbacks and operationaldifficulties are introduced thereby.

Applicants solution of this problem. is illustrated in FIG. 2 wheresimilar disc paddle electrodes 18 and 19 are placed in contact with theskin of the patient. By providing a line of electrical contact 20 at theupper surface 21 of the paddle which is equipositioned thereon, thecurrent distribution as shown by lines 22 is of equal density. The termequiposition" is herein defined to mean a line of contact which isequidistant from the center 23 of the disc paddle and the outerperipheral edge 24. This, of course, could be applied to shapes otherthan circular such as elliptical discs, squares, etc. Thus, it merelyremains to join the connecting wires 25 and 26 from the energy source 27to the paddle electrodes along such an equiposition closed loop line. Itis clear that many intervening coupling means of various shapes could beemployed and, for the sake of illustration the most regular has beenselected, namely a hollow metallic or electrical conducting cone 28. Thebase is connected by any suitable means such as brazing, soldering, etc.to the electrode and the connecting wires to the apex 29, thereof. Thusthis form of a paddle causes the current to spread out equally over theentire surface of the paddle to provide a wide area of defibrillationcurrent.

In the operating embodiment of the invention shown in FIG. 3, a cable 30which carries both the switch wires 31 and 32 and the defibrillationenergy wire 33 enter the upper handle portion 34 and can be moldedtherein. The handle 34 can be molded integral with the depending stem 35and the lower outwardly extending protector 36 the entire structurebeing of a suitable dielectric plastic as for example Bakelite. Theupper face 37 of the handle 34 is provided with a longitudinal recess 38wherein a switch arm 39 is pivotally supported at 40 for movement towardand away from the handle. The lower central portion of the switch arm 39carries an extension 41 which is in line with the movable trip 42 ofmicroswitch 43 to which the switch wires 31, 32 are connected. Thestructure may also be provided with a biasing means 44' in addition tothat of the microswitch urging the switch handle upwardly so that whenthe switch handle is released it will cause the normally openmicroswitch to assume that position. A detent or extension 44 oppositethe pivot 40 limits the upper movement of the handle 39.

The wire 33 which carries the defibrillation current and voltage fromthe source 45 passes downwardly through the stem 35 and terminates atthe apex 46 of hollow metallic cone 47. The lower peripheral edge 48 ofthe cone 47 is electrically connected in any suitable manner to the baseelectrode 49 which may be a nickel plated brass contact disc imbedded orsupported central of the lower protector portion 36. In use, theoperators hand grips completely around the handle 34 and extends overthe switch so as to throw" the switch and permit single handed utility.The lower winged protector portion shields the operators hand againstthe electrical potential.

FIGS. 4 and 5 clearly illustrate the relationships of the partsdescribed above for both a top and side elevation.

FIGS. 6 and 7 illustrate another embodiment wherein the entire structurewith the exception of the contact base electrode is identical to thatpreviously described. The base contact electrode here consists of ametallic washer-like disc 50 to whose upper surface 51 andequipositioned thereon is the base of metallic cone 52 affixed along aring 53. The inner open area of the washer disc 50 is filled with adielectric plastic disc 54 and the peripheral edge of the disc 50 isextended by a disc ring 55 of similar plastic. This same configurationcould be accomplished by imbedding or molding the contact washer 50 intothe plastic and affixing the outer edge 56 to the molded lower portion57. This configuration provides improved electrical isolation andprotection for both the operator and the patient.

It should be understood, of course, that the foregoing disclosurerelates to only a preferred embodiment of the invention and thatnumerous modifications or alterations may be made therein withoutdeparting from the spirit and the scope of the invention as set forth inthe appended claims.

I claim:

1. A pair of electrical contact paddles for providing a uniform currentdistribution from paddle to paddle through the body of a patientintermediate the paddles each of which comprises:

an electrically conducting base electrode,

an electrically conducting coupling means affixed to one face of saidelectrode along a closed line loop equipositioned between the electrodecenter and its outer edge whereby when current is applied to saidelectrodes through said coupling means the current between saidelectrodes is distributed uniformly through the body of said patient.

2. The paddles according to claim 1 wherein said electrodes are circulardiscs and said coupling means is a hollow electrically conducting conehaving its base edge electrically connected to said electrodes at saidclosed line loop.

3. The paddles according to claim 1 further including:

a dielectric housing carrying said electrodes and said coupling means.

4. The paddles according to claim 3 wherein said housing comprises:

an upper handle portion having a depending central stem affixed to andcarrying a lower outwardly extending protector portion,

said protector portion having affixed to and facing outwardly thereofsaid electrode and having therein said cone.

5. The paddles according to claim 4 further including an electricalswitch carried by one of said housings and a switch actuator handlefacing outwardly of and carried by said handle portion on said onehousing for selectively operating said switch.

6. The paddles according to claim 5 further including means for biasingsaid switch handle and means for limiting the movement thereof.

7. The paddles according to claim 1 wherein said electrode is an annularmember.

1. A pair of electrical contact paddles for providing a uniform currentdistribution from paddle to paddle through the body of a patientintermediate the paddles each of which comprises: an electricallyconducting base electrode, an electrically conducting coupling meansaffixed to one face of said electrode along a closed line loopequipositioned between the electrode center and its outer edge wherebywhen current is applied to said electrodes through said coupling meansthe current between said eLectrodes is distributed uniformly through thebody of said patient.
 2. The paddles according to claim 1 wherein saidelectrodes are circular discs and said coupling means is a hollowelectrically conducting cone having its base edge electrically connectedto said electrodes at said closed line loop.
 3. The paddles according toclaim 1 further including: a dielectric housing carrying said electrodesand said coupling means.
 4. The paddles according to claim 3 whereinsaid housing comprises: an upper handle portion having a dependingcentral stem affixed to and carrying a lower outwardly extendingprotector portion, said protector portion having affixed to and facingoutwardly thereof said electrode and having therein said cone.
 5. Thepaddles according to claim 4 further including an electrical switchcarried by one of said housings and a switch actuator handle facingoutwardly of and carried by said handle portion on said one housing forselectively operating said switch.
 6. The paddles according to claim 5further including means for biasing said switch handle and means forlimiting the movement thereof.
 7. The paddles according to claim 1wherein said electrode is an annular member.